bugfix: DefaultFailureHandler check status NPE, cause trx finished

[slievrly]

Signed-off-by: slievrly slievrly@163.com

Ⅰ. Describe what this PR did

bugfix: DefaultFailureHandler check status NPE, cause trx finished

Ⅱ. Does this pull request fix one issue?

fix #1312

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1313 into develop will increase coverage by 0.01%.
The diff coverage is 0%.

@@              Coverage Diff              @@
##             develop    #1313      +/-   ##
=============================================
+ Coverage      48.65%   48.67%   +0.01%     
  Complexity      1643     1643              
=============================================
  Files            332      332              
  Lines          11515    11517       +2     
  Branches        1422     1423       +1     
=============================================
+ Hits            5603     5606       +3     
  Misses          5291     5291              
+ Partials         621      620       -1

Impacted Files	Coverage Δ	Complexity Δ
.../java/io/seata/server/coordinator/DefaultCore.java	59.64% <0%> (-0.71%)	24 <0> (ø)
...server/store/file/FileTransactionStoreManager.java	47.03% <0%> (+1.04%)	19% <0%> (ø)	⬇️

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[ujjboy]

LGTM

[xingfudeshi]

LGTM.